Mercury switch



Nov. 16 1926. 1,607,549

. R. D.- MAILEY MERCURY SWITCH Filed Oct. 27, 1923 2 Sheets-Sheet 1 \NVENTOR Patented Nov. 16, 1926. v

UNITED STATES PATENT OFFICE.

' ROY D. MAILEY, OF EAST ORANGE, NEW JERSEY, ASSIGNOR T0 COOPER-HEWITT ELEC- v i TRIO COMPANY, A CORPORATION OF NEW JERSEY.

Mrincmw SWITCH.

Application filed October 27, 1923. Serial No. 671,104.

. My present invention relates to switches for electric circuits in which movements of the liquid mercury in said switches achieve the making and breaking of the electric conducting path therethrough. It particularly relates to such a switch in which provision is made for the automatic opening thereof at normal or at excessive temperatures when the switch is used with heating apparatus or apparatus which becomes or may become heated during use and availing of the temand closed.

perature of the heating device to cause the transfer of the liquid mercury from between the terminals of the switch to open the circuit therethrough.

.Electric heating apparatus especially of the domestic types are a recognized source of fire hazard and this is especially true in the case of electrically heated flat irons although my invention is applicable to heat ing or heated apparatus in the arts generally. Many devices are known whose'object it is to eliminate or circumvent this hazard but heretofore results therewith have not been entirely satisfactory.

It is the object of my invention to provide a switch for electrical heating apparatus which will automatically open. the circuit .t-herethrough when such devices are left standing with the current turned on through the switch.

It is another object of my invention to provide such a thermostatic switch which is simple of operation, fool proof, and simple of construction. 1

It is another object of m invention to provide such a switch which will automatically open when the device in-which-itis .used is out of its normal position.

It is another object of my invention to provide an electric flat iron switch-which will continue to function to open at normal or excessive temperatures. which is automatically closed by the motion of the iron in its use, but will function to open and remain open if left standing in the operating position. r

Fig. 1 is an elevation view of my switch in section showing it in its normal position Fig. 2 is an elevation View of my switch in section showing a part of the mercury as havingmoved from the circuit making position whereby the switch is opened.

Fig. 3 is a view in section of my switch a tilted in the plane of its width and showing opening operation of switch in this position.

Fig. 4 is a view in section of my switch through disrupted.

Fig. 7 is a vertical sectional View of the third form of my invention.

Fig. 8 is a vertical sectional view in this third form showing the operation thereof through movements of the mercury therein.

Fig. 9 is an inverted sectional view of this third'form showing the disruption of the electric path from the movements of the mercury therein as a result of this inversion.

Fig. 10 is a vertical sectional view electrically heating flat iron to which the switch 7 of my invention is applied.

Fig. 11 is an elevation view of a switch embodying my invention in which the elec trode leads are sheathed in surrounding tubes extending below the lower extremities of the electrodes and providing spaces at the terminals for the making and breaking ot' arcs between the electrodes'and the mercury body.

Fig. 12 is an elevation of a U-tube switch having mercury therein, electrodes in the legs of the U, and a condensing chamber for each of the legs near its top.

Fig. 13 is a plan view of theswitch of Figure 12.

. Fig. 14 is a side elevation view of the switch of Figure 12.

The device of my invention comprises a. body of mercury, or of some other movable and vaporizable substance electrically conductive in the useable state, which is enclosed in the chamber" of a vitreous envelope of such material as glass. Through the walls of the envelope and in contact with the said body of mercury, for example, are sealed electrical conductors which on their outer ends are suitably connected to electric mains and heating apparatus. Connecting with the said chamber near its top is a con- (lensing chamber for the condensation and collection therein of vaporized mercury or the like passing thereto from the main chamber. Means is provided for preventing the flow of the condensed mercury back into the main chamber. Such means as described below and shown in the drawings are embodied in a lower floor or boundary for such condensing chamber which recedes from the main chamber to form with the other walls of said chamber a liquid collecting pocket. Another embodiment shown and described is a raiied rim or ridge at the confluence of the two chambers which rim or ridge serves as a dam to hold back and collect condensed liquid in the condensing chamber. Such re-- cession of the floor orsuch raising of a rim is of such degree as to permit, for instance in the use of my switch in an electric heated flat iron, of a constant and continuous return of the mercury or other liquid collected in the condensing chamber through the normal movement of the iron in its use for ironing. When the iron is inuse and the switch in almost constantmotion the condensed mercury is continually returned to the main body and the. switch left cloted. Any cessation of motion will mean the accumulation of mercury in the condensing chamber and a continuation thereof will result in the o ening of the switch, and the discontinuing 0 current supply to the heating element, and the cooling of the iron. Further, some forms of the device of my invention provide therein can be easily and quickly moved back to the main chamber by asimple movement of the switch or of the apparatus in which the-switch is installed or by its normal movement in the use of the apparatus in which it is installed.

As an exampleI shall defcribe the use of the switch of my invention in connection with an electrically heated flat iron.

In the drawings is shown anenvelope 1 as of glass having a condensing subchamber near its top and the level of the bottom boundary of which lowers away from the main chamber. Through the walls of the envelope 1 are sealed electrodes 3 and 4: which in the normal position and condition of the switch are connected by thebody of mercury, 2 within said envelope. Under normal operating or BXCGI'SlVQ temperature, a part of the body of mercury 2 will be distilled therefrom passing into the subchamher or pocket 5 where it will condense and accumulate as shown in Figures2, 3, 4, 5 and 8 of the drawings. This distillation and accumulation will continue while such normal or excessive temperature is maintained when the switch is at rest until sufiicient mercury parses from the main body 2 to disrupt the electrical conducting path between electrodes 3 and l: as shown in Figures 2, 3,

a and 8.

Figure 3 which shows the switch tilted in I the plane of the switch and in the direction of the pocket 5, also shows the movement of mercury therein by distillation and condensation into said pocket 5 to open the circuit between the terminals of the switch.

ing of the circuit through the switch. In

Figures 5 and 6 I have shown the electrodes 3 and 4 which extend downwardly from the top of the envelope. to the mercury contained therein, as in the form shown in Figure 1, as being coated with the material of the envelope body to Within a short distance of their inner ends or with some other suitable material. In this form upon change of position of the switch from a position in which pocket 5' will hold and accumulate mercury, the mercury will flow away from one or both of the electrodes 3 and 4 to disrupt the electrical conducting path therebetween. An example of the extreme position of this sort isshown in Figure6 where a switch is inverted and mercury has flowed completely away from electrodes 3 and 4. Between this extreme position and Inn lOS

the normal position of the switch this form of my invention is designed to function to open the circuit therethrough either by the flowing of the mercury away from the electrodes on the assumption of such position to disrupt the electrical conducting path therebetween or to evaporate, condense and accumulate mercury in said pocket 5 when the switch is subjected to normal or'excessive temperature whereby the electrical path through said switchis opened.

- In Figures 7, 8 and 9 is depicted a third form of my invention which operates in the same manner as that of the second form which is shown in Figures and 6. In this third form electrodes .8 and 9 thereof are sealed in through the bottom of the envelope 1 and are coated Within a short distance of their inner ends by the material of the envelope body and continuous therewith or by some other suitable material. It is clear in this form of my invention that the electrodes can be sealed'into the envelope body at any desired position through the walls thereof. v

In Figure is shown flat iron 10 into the body of which is inserted the lower part of the switch envelope 1 the said lower part situated near the heating element 11 of the iron and showing the subchamber or pocket 5 as situated outside and away from said heating element. Said lower boundary of the subchamber or pocket 5 is approximately a plane or is of such shape that when the switch is sufiiciently tilted in the direction away from said pocket that any mercury therein will flow back into the main chamber 1. In this position the main body of mercury 2 is subjected to the temperature of the iron while the subchamber or pocket 5 remains always at a much lower temperature when the iron is heated and at a temperature at which any mercury distilled therefrom will condense and accumulate therein.

In the operation of the first form of the device of my invention. using the electrical heated flat iron application as an example, when the flat iron is in its normal'position and current turned thereon a conducting path will continue therethrough until a tem-' perature is reached such that will cause the distillation of mercury vapor from the mercury body 2 and the passing thereof to pocket 5 and the condensation thereof in said pocket where it will accumulate in body 6. This distillation, accumulation, and condensation will continue while such temperature prevails until the conducting path between electrodes 3 and 4 is disrupted and the current through said heating element 11, is discontinued whereupon the temperature in said iron lowers and any danger of fire hazard through it is averted. To return the mercury 6 to the main body of mercury 2 the iron is simply shaken or tilted to cause said mercury 6 to flow back to the body 2. g

In Figure 11 is shown a form of my invention in which the electrodes 3 and 4 are sealed through the top of the envelope 1 of the switch, each of said electrodes being surrounded by the glass tubes 12 which extend beyond the inner ends of the electrodesto provide restricted spaces about saidends and which serve to a degree to quench or dissipate any arcing that takes place on the movement of the mercury away from such ends. About midway between the ends of such tubes 12 are the holes, 13 which-serve to equalize vapor pressures throughout said tubes 12 and the interior of envelope 1. The rim 14 between chamber and condensing chamber 5 is of such height as to hold sufficient mercury on the substantially horizontal floor 15 of chamber 5 to result in the opening of the circuit between electrodes 3 and 4.

In Figures 12, 13, and 14 is shown the switch body 16 which is substantially a sealed U-tube to the upper part of the legs 17 of which connect the condensing chamber 18, 18. The electrodes?) and dare sealed in through the tops of the legs 17 and extend into the mercury body 2. In this form of my invention upon the evaporation of mercury, from body 2 and its condensation and any arcing which might occur between the electrodes and the mercury in cases where the current therethrough is heavy enough to sustain an arc the carrying on of the arc to the electrodes themselves is prechamber and a condensing chamber, a conducting liquid in said main chamber, and electrodes sealed through the walls of the envelope and extending into said liquid...

2. In a switch, in combination, a sealed envelope having a main chamber and a condensing chamber, vaporizable material in said -main chamber, and electrodes sealed through the walls of said envelope and connecting electrically with said vaporizable material.

3. In a mercury switch, in combination, a sealed envelope comprising-a main chamber and a condensing chamber connecting therewith, and electrodes sealed through the walls of said envelope and connecting electrically with said mercury, said condensing chamber forming a pocket to accumulate and hold mercury condensed therein.

4:. In a mercury switch, in combination, a sealed envelope comprlsing a main chamber and a condensing chamber connecting therewith, a body of mercuryin the bottom of said main chamber, electrodes sealed through the walls of said envelope and extending into said body of mercury, and a vitreous coating on said electrodes extending from the point of sealing-in to short distance of the ends of the electrodes.

5. In a, mercury switch, in combinatioma sealed envelope comprising a main chamber and a condensing chamber, a body fof mercury in said main chamber, electrodes sealed through the walls of said envelope and extending into said body of mercury, and insulating coatings of vitreous material on said electrodes fused to the wall of the envelope at the seal-ins and extending to within a short distance of the inner ends of said electrodes, the lower floor of said condensing chamber receding slightly downwardly away from the confluence of the two said chambers.

Signed at Hoboken in the county of Hud- 

